I have a Dell XPS 13 9350. It runs Windows 10. It is the latest insider preview, but this issue has appeared and disappeared, even on the stable builds.
When I put the computer to sleep, either by choosing 'sleep' from the shutdown option in Start, or by closing the lid, it turns off the screen, only for it to turn on again with airplane mode enabled. The computer remains active and does not go in low-power mode, leading to drained batteries.
I've already run
powercfg -requests but nothing seems to keep the computer awayke. I have a dualboot setup with Ubuntu 16.04 which sleeps just fine, so it's definitely Windows. Any ideas as to what might cause this?
Edit: I also noticed that issuing the Sleep command a second time (after it turns on Airplane mode), will disable airplane mode. It's like Sleep means: log out and switch on airplane mode, instead of: sleep.